The purpose of this application is to request travel support for five U. S. scientists to participate in a Symposium to be held at the Annual Meeting of the American Association for the Advancement of Science (AAAS). Cell surface receptors appear to be involved in many biological processes. Much of the important work in this area relates to studies of human disease; Science and medicine are tightly intertwined. In fact, some of the most important data about receptors come from disease states. This particular subject was selected by the APS as one for which presentation to a broad audience of Scientists, as represented by AAAS, is most timely.